The present application describes systems and techniques relating to extreme ultraviolet light sources, for example, extreme ultraviolet light sources used in extreme ultraviolet light lithography or interferometry.
Traditionally recognized extreme ultraviolet (EUV) light sources include synchrotrons and plasma-based sources. A synchrotron is an annular particle accelerator that can produce synchrotron radiation or a free electron laser using wiggler magnets. Synchrotrons are generally large and expensive high energy devices, which may be able to radiate in the EUV region.
Plasma-based sources of EUV light include electric discharge plasma sources and laser discharge plasma sources. Typically, a jet of xenon gas is excited into a plasma using a laser or electricity. The plasma then provides atomic spectral radiation in the EUV range. Plasma-based EUV sources generate high energy ions, which tend to sputter any materials that fall in a line of sight of the plasma. Additionally, plasma-based EUV sources tend to have low energy efficiency and use extensive cooling systems.
Details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features and advantages may be apparent from the description and drawings, and from the claims.